tests: Test g_list_model_get_object()
tests: Test g_list_model_get_object()

It wasn’t being tested. It should behave the same as
g_list_model_get_item(), so write a wrapper for the two.

This brings the code coverage of glistmodel.c up to 100%.

Signed-off-by: Philip Withnall <29c2a2ac2a854b9cf047275aa9de346d096be2e0@endlessm.com>

endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib